Comparison of Analgesic Efficacy of Levobupivacaine with or without Dexamethasone in Lower Abdominal Surgeries under Subarachnoid Block: A Pilot Randomised Controlled Trial

Abstract

Introduction: Subarachnoid Block (SAB) is a commonly used technique for lower abdominal surgery. Dexamethasone has been proven effective as an additive when used with bupivacaine. However, there has been no study comparing the analgesic efficacy of dexamethasone with levobupivacaine under SAB. Aim: To compare the analgesic efficacy of levobupivacaine with or without dexamethasone in patients scheduled for lower abdominal surgeries. Materials and Methods: A pilot randomised doubleblind controlled trial was undertaken in the Department of Anaesthesiology, University College of Medical Sciences Guru Tagh Bahudur (UCMS-GTB) Hospital, New Delhi, India on 60 patients with Americian Soceity of Anaesthesiolgy (ASA) grade I or II, aged 18-65 years, undergoing lower abdominal surgeries under SAB from January 2021 to August 2022. In Group LS, 12.5 mg of 0.5% isobaric levobupivacaine (2.5 mL) with normal saline (1 mL) was administered, and in Group LD, 12.5 mg of 0.5% isobaric levobupivacaine (2.5 mL) with 4 mg dexamethasone (1 mL) was given. Patients were assessed for sensory and motor block, haemodynamic parameters, pain score, and side-effects. Unpaired t-tests/Mann-Whitney U tests were used to determine significance. A p-value of less than 0.05 was considered significant. Results: The two groups were comparable in terms of demographic profile. The age in the LS group was 37.80±9.98 years, and in the LD group, it was 38.63±12.37 years. The maleto-female ratio in the LS and LD groups was 17:13 and 21:9, respectively. The weight range in both groups was between 50 to 67 kg. The Basal Metabolic Index (BMI) was 22.40±2.43 kg/ m2 and 21.70±2.21 kg/m2 in the LD and LS groups, respectively. All these parameters, including height, had a p-value of more than 0.005, except for the duration of analgesia. The duration of effective analgesia was also longer in the LD group (247.00±36.69 min) than in the LS group (138.50±22.52 min) with a p-value of <0.001. The time of onset of sensory block was 9.13±2.98 minutes in the LD group and 10.30±3.06 minutes in the LS group, which was statistically insignificant. Conclusion: Authors concluded addition of 4 mg (1 mL) of dexamethasone to 2.5 mL of 0.5% isobaric levobupivacaine provides a clinically longer duration of effective analgesia with early onset and better quality of sensory and motor block than 2.5 mL of 0.5% isobaric levobupivacaine alone. Therefore, 4 mg of dexamethasone with 2.5 mL of 0.5% isobaric levobupivacaine is recommended for lower abdominal surgeries under SAB.